CN209962694U - Echo cancellation circuit and electroacoustic equipment - Google Patents
Echo cancellation circuit and electroacoustic equipment Download PDFInfo
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- CN209962694U CN209962694U CN201920293190.9U CN201920293190U CN209962694U CN 209962694 U CN209962694 U CN 209962694U CN 201920293190 U CN201920293190 U CN 201920293190U CN 209962694 U CN209962694 U CN 209962694U
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Abstract
The utility model discloses an echo cancellation circuit and an electroacoustic device, which comprises a power amplification module, a loudspeaker, a microphone, an echo cancellation module and a filter circuit; the filter circuit is used for transmitting the collected voice reference signal sent by the power amplifier module to the echo cancellation module, the microphone is used for collecting an external mixed voice signal and transmitting the external mixed voice signal to the echo cancellation module, and the echo cancellation module is used for acquiring the mixed voice signal and canceling an echo in the mixed voice signal according to the voice reference signal. The utility model discloses utilize filter circuit to reduce echo reference signal's noise, promoted echo cancellation's effect.
Description
Technical Field
The utility model relates to a circuit electron field especially relates to echo cancellation circuit and electroacoustic equipment.
Background
The echo generated during voice communication is mainly acoustic echo. The acoustic echo is that a sound emitted from a loudspeaker of the communication equipment is received by a microphone and transmitted to another party of communication together with the own voice of a speaker during the communication process of a user, so that the user of the other party can hear the own voice. In the prior art, a voice signal is amplified and the like by a power amplifier, and the processed voice signal is used as a reference signal of echo. And then eliminating the echo signal in the mixed voice signal received by the microphone according to the obtained echo reference signal by using the adaptive filter and the adaptive algorithm. However, after the power amplifier amplifies and the like the voice signal, the generated echo reference signal will contain a large amount of high-frequency noise and carrier, and the echo cancellation effect will be seriously affected by the echo cancellation using the echo reference signal containing the noise.
SUMMERY OF THE UTILITY MODEL
A primary object of the present invention is to provide an echo cancellation circuit and an electroacoustic apparatus, wherein the reference signal for solving the echo contains noise and affects the echo cancellation effect.
In order to achieve the above object, the present invention provides an echo cancellation circuit, which includes a power amplifier module, a speaker, a microphone, an echo cancellation module, and a filter circuit;
the output end of the power amplifier module is respectively connected with the loudspeaker and the input end of the filter circuit, the output end of the filter circuit is connected with the first input end of the echo cancellation module, and the output end of the microphone is connected with the second input end of the echo cancellation module;
the filter circuit is used for transmitting the collected voice reference signal sent by the power amplifier module to the echo cancellation module, the microphone is used for collecting an external mixed voice signal and transmitting the external mixed voice signal to the echo cancellation module, and the echo cancellation module is used for acquiring the mixed voice signal and canceling an echo in the mixed voice signal according to the voice reference signal.
Optionally, the filter circuit includes a first resistor, a first capacitor, a second capacitor, and a voltage dividing resistor; the one end of first resistance with the output of power amplifier module is connected, first resistance with divider resistance establishes ties, divider resistance keeps away from the one end ground connection of first resistance, first electric capacity with divider resistance is parallelly connected, the one end of second electric capacity with first resistance is close to divider resistance's one end is connected, the other end of second electric capacity with the first input of echo cancellation module is connected.
Optionally, the filter circuit further includes a second resistor and a third capacitor, one end of the second resistor is connected to one end of the first resistor close to the divider resistor, the other end of the second resistor is connected to one end of the second capacitor far away from the echo cancellation module, one end of the third capacitor is connected to one end of the second resistor close to the second capacitor, and the other end of the third capacitor is grounded.
Optionally, the echo cancellation circuit includes a first ADC module, one end of the first ADC module is connected to the output end of the filter circuit, and the other end of the first ADC module is connected to the first input end of the echo cancellation module.
Optionally, the echo cancellation circuit further includes a delay module, and an output end of the filter circuit is connected to the first input end of the echo cancellation module through the delay module.
Optionally, the echo cancellation circuit further includes a second ADC module, one end of the second ADC module is connected to the output end of the microphone, and the other end of the second ADC module is connected to the second input end of the echo cancellation module.
Optionally, the echo cancellation circuit further includes a differential input circuit, and the output end of the microphone is connected to the end of the second ADC module far away from the echo cancellation module through the differential input circuit.
Optionally, the echo cancellation circuit further includes a pre-amplifier circuit, an output end of the microphone is connected to one end of the pre-amplifier circuit through the differential input circuit, and the other end of the pre-amplifier circuit is connected to the second input end of the echo cancellation module.
Optionally, the echo cancellation circuit further includes a DAC module and a voice signal output terminal, and an input terminal of the power amplifier module is connected to the voice signal output terminal through the DAC module.
Further, in order to achieve the above object, the present invention also provides an electroacoustic apparatus including an echo canceling circuit connected to a voice signal output terminal, the echo canceling circuit being configured as the echo canceling circuit described above.
The utility model is provided with a power amplifier module, a loudspeaker, a microphone, an echo cancellation module and a filter circuit; when receiving the voice signal, the power amplification module amplifies the voice signal and sends out corresponding voice through the loudspeaker. The filter circuit is used for collecting voice reference signals from the power amplifier module and filtering high-frequency noise in the voice reference signals, the microphone is used for receiving echo signals sent by the loudspeaker and voice signals sent by a user, the voice reference signals collected by the filter circuit are transmitted to the echo cancellation module, and mixed voice signals which are received by the microphone and are formed by mixing the echo signals and the voice signals of the user are also transmitted to the echo cancellation module. And the echo cancellation module performs echo cancellation processing on the mixed voice signal according to the voice reference signal so as to obtain the voice signal of the user after echo cancellation. The voice reference signal is filtered through the filter circuit, high-frequency noise or clutter in the voice reference signal can be filtered, so that an accurate voice reference signal can be obtained, and the echo cancellation module can achieve a high-precision echo cancellation effect according to the accurate voice reference signal.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a schematic block diagram of an embodiment of an echo cancellation circuit according to the present invention;
fig. 2 is a schematic circuit diagram of the filter circuit in the embodiment of fig. 1.
The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) |
| 10 | |
11 | |
| 12 | Microphone (CN) | 13 | |
| 14 | |
20 | |
| 30 | Second ADC module | R1 | A first resistor |
| R | Voltage dividing resistor | R2 | Second resistance |
| C1 | First capacitor | C2 | Second capacitor |
| C3 | |
40 | |
| 50 | Pre-amplifier circuit |
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit ly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.
The utility model provides an echo cancellation circuit is applied to among the electroacoustic equipment, and this electroacoustic equipment can be mobile phone, fixed telephone, PC, panel computer, smart television, intelligent audio amplifier etc..
Referring to fig. 1, in an embodiment, the echo cancellation circuit includes a power amplifier module 14, a speaker 13, a microphone 12, an echo cancellation module 10, and a filter circuit 11; the signal receiving end of the power amplifier module 14 is connected to the output end of the voice signal, two signal output ends of the power amplifier module 14 are respectively connected to the receiving end of the speaker 13 and the input end of the filter circuit 11, the output end of the filter circuit 11 is connected to the first input end of the echo cancellation module 10, and the output end of the microphone 12 is connected to the second input end of the echo cancellation module 10.
The filter circuit 11 is configured to collect a voice reference signal output by the power amplifier module 14, and transmit the voice reference signal to the echo cancellation module 10; the microphone 12 is configured to collect a mixed voice signal formed by mixing a voice signal sent by an external user and an echo signal sent by the speaker 13, and transmit the mixed voice signal to the echo cancellation module 10. After acquiring the mixed voice signal and the voice reference signal, the echo cancellation module 10 performs echo cancellation processing on the mixed voice signal according to the voice reference signal to cancel an echo in the mixed voice signal.
The echo cancellation circuit provided in this embodiment is specifically disposed in an electronic device capable of performing voice communication. After receiving the voice signal, the power amplifier module 14 processes the voice signal and outputs the processed signal to the speaker 13 and the filter circuit 11, respectively. After receiving the analog signal of the voice signal sent by the power amplification module 14, the speaker 13 can send out voice according to the analog signal, so that the user can hear the voice from the speaker 13. The filter circuit 11 can receive the voice signal sent by the power amplifier module 14 and use the voice signal as the voice reference signal for echo cancellation. After the voice signal is low-pass filtered by the filter circuit 11, the noise part of the high frequency band in the voice signal can be effectively filtered, only the voice signal of the low frequency band is reserved as the voice reference signal, and the voice reference signal is sent to the echo cancellation module 10. The microphone 12 can receive a mixed voice signal from the outside, wherein the mixed voice signal includes voice uttered by the user, ambient sounds from the outside, and an echo uttered by the speaker 13, and the microphone 12 can transmit the mixed voice signal to the echo cancellation module 10. The echo cancellation module 10 includes an adaptive filter, and after receiving the mixed speech signal and the speech reference signal, the adaptive filter can establish a speech signal model based on the correlation between the speech reference signal and the echo of the speaker 13 in the mixed speech signal received by the microphone 12, and adjust the model by an adaptive algorithm, so that the impulse response calculated according to the speech reference signal is close to the echo of the speaker 13. The echo signal in the mixed voice signal can be eliminated by subtracting the impulse response signal obtained by calculation from the mixed voice signal.
In this embodiment, through the combined design of the power amplifier module 14, the speaker 13, the microphone 12, the echo cancellation module 10, the filter circuit 11, and the like, the echo of the speaker 13 can be accurately cancelled in the electroacoustic device, so that the user can avoid hearing the sound emitted by the user from the speaker 13, and the call quality of the voice communication is improved. Because the filter circuit 11 can filter the high-frequency band noise in the speech reference signal, only the actual speech signal of the low-frequency band is retained, so that the speech reference signal acquired in the echo cancellation module 10 is more accurate, and the echo cancellation effect is further improved.
Specifically, the echo cancellation formula of the adaptive filter is:
wherein ω is a time domain impulse response function of the echo of the speaker 13, x is a voice signal sent by the far end, and echo is the echo of the speaker 13 actually received by the microphone 12; d is a mixed voice signal actually acquired by the microphone 12, and s represents a voice signal excluding the echo signal in the mixed voice signal acquired by the microphone 12, and mainly includes an ambient sound and a voice signal of the user; omega ^ is a pre-estimated time domain impact response function obtained by calculating the collected voice reference signal in the adaptive filter, and y ^ is a pre-estimated echo signal obtained by calculating according to the voice reference signal; e represents the error between the actual echo signal and the estimated echo signal, and the value of the error can be reduced by continuously modifying the adaptive algorithm, so that the accuracy of echo cancellation is greatly improved.
Further, referring to fig. 2, for example, the filter circuit 11 may include a first resistor R1, a first capacitor C1, a second capacitor C2, and a voltage dividing resistor R; one end of the first resistor R1 is an output end of the power amplifier module 14, the first resistor R1 is connected in series with the voltage dividing resistor R, one end of the voltage dividing resistor R far away from the first resistor R1 is grounded, the first capacitor C1 is connected in parallel with the voltage dividing resistor R, one end of the second capacitor C2 is connected with one end of the first resistor R1 close to the voltage dividing resistor R, and the other end of the second capacitor C2 is connected with a first input end of the echo cancellation module 10.
Optionally, the filter circuit 11 may further include a second resistor R2 and a third capacitor C3, one end of the second resistor R2 is connected to one end of the first resistor R1, which is close to the voltage dividing resistor R, the other end of the second resistor R2 is connected to one end of the second capacitor C2, which is far away from the echo cancellation module 10, one end of the third capacitor C3 is connected to one end of the second resistor R2, which is close to the second capacitor C2, and the other end of the third capacitor C3 is grounded.
After the filter circuit 11 receives the voice reference signal output by the power amplifier module 14 from the power amplifier module 14, the filter circuit 11 can filter the signal of the high frequency band in the voice reference signal, and only outputs the voice reference signal of the low frequency band to the echo cancellation module 10, because the power amplifier module 14 will cause the processed voice signal to include a large amount of high frequency carriers and noises when processing the voice signal of the far end, the voice signal of these high frequencies is not the voice signal of the far end, the echo cancellation module 10 will provide wrong correlation basis when performing echo cancellation by using the voice reference signal including the high frequency noise, which results in the serious reduction of the echo cancellation effect. The filtering circuit 11 filters the noise in the high frequency band, so that the echo cancellation module 10 can obtain an accurate reference signal of the far-end speech, thereby implementing the echo cancellation function.
Optionally, the echo cancellation circuit described with continued reference to fig. 1 may further include a first ADC module 20 and a second ADC module 30, where the ADC modules are analog signal/digital signal conversion modules, the filter circuit 11 is connected to the first input end of the echo cancellation module 10 through the first ADC module 20, and the first ADC module 20 can convert an analog signal sent by the filter circuit 11 into a digital signal and transmit the digital signal to the first input end of the echo cancellation module 10; the output end of the microphone 12 is connected to the second input end of the echo cancellation module 10 through the second ADC module 30, and the second ADC module 30 can convert the analog signal output by the microphone 12 into a digital signal and transmit the digital signal to the second input end of the echo cancellation module 10.
Optionally, the echo cancellation circuit further includes a delay module, since the filter circuit 11 can directly transmit the voice reference signal to the echo cancellation module 10, and the microphone 12 needs to collect the echo signal of the speaker 13 after the speaker 13 sends out the voice, a certain time difference exists between the mixed voice signal of the microphone 12 and the voice reference signal of the filter circuit 11, that is, the voice reference signal is collected by the echo cancellation module 10 earlier than the mixed voice signal. Therefore, a delay module is added between the filter circuit 11 and the echo cancellation module 10, so that the echo cancellation module 10 can perform echo cancellation according to the voice reference signal corresponding to the mixed voice signal, and it is avoided that the reference signal of echo cancellation cannot be applied due to a time error.
Further, the echo cancellation circuit may further include a differential input circuit 40 and a pre-amplifier circuit 50, and the differential input circuit 40 and the pre-amplifier circuit 50 may be separately or mixedly disposed between the output terminal of the microphone 12 and the second input terminal of the echo cancellation module 10. It should be noted that the differential input circuit needs to be disposed before the preamplifier circuit, and both the differential input circuit and the preamplifier circuit need to be connected to the second input terminal of the echo cancellation module through the second ADC module. The differential input circuit 40 and the pre-amplifier circuit 50 can effectively amplify and output the mixed voice signal collected by the microphone 12, so that the gain of the mixed voice signal that can be received by the echo cancellation module 10 is increased, and the echo cancellation effect is further improved.
Optionally, the echo cancellation circuit further includes a DAC module, an input end of the power amplifier module 14 is connected to an output end of the voice signal through the DAC module, and the DAC module can convert the digital signal into an analog signal, so that the power amplifier module 14 can obtain the analog signal of the voice signal and amplify the analog signal.
The utility model also provides an electroacoustic equipment, electroacoustic equipment can be mobile phone, fixed telephone, PC, panel computer, smart television or intelligent audio amplifier etc.. The electroacoustic device comprises an echo cancellation circuit connected to the speech signal output terminal, and the structure of the echo cancellation circuit is as described in the above embodiments, and is not described herein again. It should be noted that, since the electroacoustic device of the present embodiment adopts the technical solution of the echo cancellation circuit, the electronic device has all the beneficial effects of the echo cancellation circuit.
The above is only the optional embodiment of the present invention, and not therefore the scope of the present invention is limited, all the equivalent structures or equivalent flow changes made by the contents of the specification and the drawings, or directly or indirectly applied to other related technical fields, are included in the same way in the protection scope of the present invention.
Claims (9)
1. An echo cancellation circuit is characterized by comprising a power amplification module, a loudspeaker, a microphone, an echo cancellation module, a time delay module and a filter circuit;
the output end of the power amplifier module is respectively connected with the loudspeaker and the input end of the filter circuit, the output end of the filter circuit is connected with the first input end of the echo cancellation module through the delay module, and the output end of the microphone is connected with the second input end of the echo cancellation module;
the filter circuit is used for transmitting the collected voice reference signal sent by the power amplifier module to the echo cancellation module, the microphone is used for collecting an external mixed voice signal and transmitting the external mixed voice signal to the echo cancellation module, and the echo cancellation module is used for acquiring the mixed voice signal and canceling an echo in the mixed voice signal according to the voice reference signal.
2. The echo cancellation circuit of claim 1, wherein the filter circuit comprises a first resistor, a first capacitor, a second capacitor, and a voltage divider resistor; the one end of first resistance with the output of power amplifier module is connected, first resistance with divider resistance establishes ties, divider resistance keeps away from the one end ground connection of first resistance, first electric capacity with divider resistance is parallelly connected, the one end of second electric capacity with first resistance is close to divider resistance's one end is connected, the other end of second electric capacity with the first input of echo cancellation module is connected.
3. The echo cancellation circuit of claim 2, wherein the filter circuit further comprises a second resistor and a third capacitor, one end of the second resistor is connected to one end of the first resistor close to the voltage divider, the other end of the second resistor is connected to one end of the second capacitor far from the echo cancellation module, one end of the third capacitor is connected to one end of the second resistor close to the second capacitor, and the other end of the third capacitor is grounded.
4. The echo cancellation circuit of claim 1, wherein the echo cancellation circuit comprises a first ADC block, one end of the first ADC block being connected to the output of the filtering circuit, the other end of the first ADC block being connected to the first input of the echo cancellation module.
5. The echo cancellation circuit of claim 1, further comprising a second ADC module, one end of the second ADC module being connected to the output of the microphone, the other end of the second ADC module being connected to a second input of the echo cancellation module.
6. The echo cancellation circuit of claim 5, further comprising a differential input circuit, wherein the output of the microphone is connected to an end of the second ADC block remote from the echo cancellation block through the differential input circuit.
7. The echo cancellation circuit of claim 6, further comprising a pre-amplification circuit, wherein an output of the microphone is connected to one end of the pre-amplification circuit through the differential input circuit, and wherein another end of the pre-amplification circuit is connected to the second input of the echo cancellation module.
8. The echo cancellation circuit of any one of claims 1-7, further comprising a DAC module and a voice signal output, wherein the input of the power amplification module is coupled to the voice signal output via the DAC module.
9. An electro-acoustic apparatus, characterized in that it comprises an echo cancellation circuit connected to a speech signal output, said echo cancellation circuit being configured as an echo cancellation circuit according to any of claims 1-8.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920293190.9U CN209962694U (en) | 2019-03-07 | 2019-03-07 | Echo cancellation circuit and electroacoustic equipment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920293190.9U CN209962694U (en) | 2019-03-07 | 2019-03-07 | Echo cancellation circuit and electroacoustic equipment |
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| CN209962694U true CN209962694U (en) | 2020-01-17 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112929722A (en) * | 2021-03-31 | 2021-06-08 | 杭州国芯科技股份有限公司 | External device for voice control of set top box |
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2019
- 2019-03-07 CN CN201920293190.9U patent/CN209962694U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112929722A (en) * | 2021-03-31 | 2021-06-08 | 杭州国芯科技股份有限公司 | External device for voice control of set top box |
| CN112929722B (en) * | 2021-03-31 | 2024-05-28 | 杭州国芯科技股份有限公司 | External equipment for voice control of set top box |
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